CAFFEINE consumption, FOOD-BORNE ILLNESSES, or
viral INFECTION(GASTROENTERITISor ENTERITIS). These
circumstances tend to resolve themselves within a
few days, which may be briefer than the actions of
many antidiarrheal medications.
Taking an antidiarrheal product may result in
rebound CONSTIPATION. However, diarrhea more
significantly interferes with daily activities than
does constipation, and many people opt to take
medications to slow or stop it. It is important to
drink extra fluids when taking antidiarrheal med-
ications, to replace fluids lost with the diarrhea as
well as to maintain adequate hydration of the gas-
trointestinal tract to prevent rebound constipation
from developing. Some antidiarrheal medications
are available over the counter and others require a
doctor’s prescription.
Doctors sometimes prescribe anticholinergic
medications, which act on the NERVOUS SYSTEMto
slow gastrointestinal function, for severe diarrhea.
However, these medications have numerous
actions throughout the body, and doctors tend to
reserve them for use when other antidiarrheal
medications are ineffective. Opiate NARCOTICSsuch
as paregoric and codeine are effective for slowing
gastrointestinal motility. Attapulgite, pectin, and
kaolin are natural substances that absorb fluid.
Though typically perceived as LAXATIVES, bulking
agents such as psyllium and methylcellulose also
absorb water and can help restore normal bowel
function.
Antidiarrheal medications are most effective for
controlling outbreaks of diarrhea such as may
occur with IRRITABLE BOWEL SYNDROME(IBS), INFLAM-
MATORY BOWEL DISEASE (IBD), andMALABSORPTION.
Antidiarrheal medications are also effective for
treating antibiotic-induced diarrhea that does not
end when the antibiotic therapy ends. Remedies
such as taking lactobacillus or eating plain yogurt
may help restore normal BACTERIAto the gastroin-
testinal tract.
The most frequent complication of antidiar-
rheal medications is rebound constipation. A rare
but serious complication that can occur when tak-
ing antidiarrheal medications that slow gastroin-
testinal motility is TOXIC MEGACOLON, in which the
colon becomes vastly dilated and flaccid and the
flow of the intestinal content stops. Antidiarrheal
medications also can mask conditions that require
medical attention. For most people, occasional use
of over-the-counter antidiarrheal medications pro-
vides prompt relief of diarrhea with few complica-
tions.
See also ANTACIDS; ANTIEMETIC MEDICATIONS; FIBER
AND GASTROINTESTINAL HEALTH.antiemetic medications Medications that relieve
NAUSEAand VOMITING(known clinically as emesis).
The most commonly used are anticholinergic
medications and antihistamineMEDICATIONS, which
suppress the vestibular system mechanisms that
cause vomiting. Many antihistamine products are
available over the counter. Doctors may recom-
mend or prescribe these medications to treat nau-
sea related to VERTIGO, MÉNIÈRE’S DISEASE,
LABYRINTHITIS, and other disorders of the inner EAR
and vestibular system, and to help prevent motion
sickness. Both anticholinergics and antihistamines
can cause drowsiness and dry MOUTH.
A classification of powerful antiemetics, the 5 -
HT 3 RECEPTOR ANTAGONIST MEDICATIONS, became
available in the 1990s. Doctors prescribe these
medications, such as dolasetron and ondansetron,
primarily to treat nausea and vomiting resulting
from RADIATION THERAPY, CHEMOTHERAPY, and sur-
gery. These medications work by blocking sero-
tonin from reaching receptors in the
gastrointestinal system and may have neurologic
side effects such as Parkinson-like symptoms.
Over-the-counter products to treat nausea
include bismuth subsalicylate (Pepto-Bismol) and
cola syrup, both of which are effective for reliev-
ing mild nausea and vomiting with viral INFECTION
(such as GASTRITISand GASTROENTERITIS). Pharmacies
also sell a commercial preparation of phosphor-
ated carbohydrate solution, similar to cola syrup,
called Emetrol. Cola drinks allowed to go “flat”
have the same antinausea effect. These substances
act to soothe the inner lining of the stomach. GIN-
GERalso has a calming action on the stomach and
can provide relief through drinking flat ginger ale
(brands that contain ginger, not just ginger flavor-
ing) or eating small pieces of fresh ginger root.
Treatment for nausea and vomiting also targets
any underlying conditions or causative circum-
stances.
See also ACUPUNCTURE; MORNING SICKNESS; NEURO-
TRANSMITTER.antiemetic medications 13